Add installation and packaging target

[NDM14]

GitLab Username: schmidpl

How to test:

1. build the docker image:
   docker build -t cpackexample .

2. Run the container:
   docker run --rm -it --mount type=bind,source="$(pwd)",target=/mnt/cpack-exercise cpackexercise

3. build the packages inside the container:
   cd /mnt/cpack-exercise mkdir build && cd build cmake .. make -j4 make package

4. test the packages inside the container:
   `dpkg-deb -c cpackexample_0.1.0_amd64.deb
   tar -tzf cpackexample-0.1.0-Linux.tar.gz

make install DESTDIR=/tmp/test-install

apt install -y ./cpackexample_0.1.0_amd64.deb
cpackexample

lintian ./cpackexample_0.1.0_amd64.deb
`

Final Lintian Output:

'
root@194e97b2f21d:/mnt/cpack-exercise/build# lintian ./cpackexample_0.1.0_amd64.deb
running with root privileges is not recommended!
E: cpackexample: no-changelog usr/share/doc/cpackexample/changelog.gz (native package)
E: cpackexample: no-copyright-file
W: cpackexample: extended-description-line-too-long line 1
W: cpackexample: no-manual-page [usr/bin/cpackexample]
'

Changes:

1. Modified CMakeLists.txt to add install targets
2. Created cmake/CPackConfig.cmake to generate debian packages
3. Inspected the debian package with linter to validate it